In 2008, a foreign intelligence agency slipped a flash drive into a U.S. military computer, sneaking malicious code onto classified military networks: "A rogue program operating silently, poised to deliver operational plans into the hands of an unknown adversary." Gulp.

That's how Deputy Defense Secretary William J. Lynn III described the incident in an article published today, with the hope that declassifying the information will help impart that computer security is an increasingly important part of national security. Pentagon officials say it's the first official disclosure that U.S. military networks have been breached by foreign intelligence.

One military official, speaking anonymously, explained the importance of keeping these classified networks secure:

This is how we order people to go to war. If you're on the inside, you can change orders. You can say, 'turn left' instead of 'turn right.' You can say 'go up' instead of 'go down.'

According to the article, the code was loaded onto a military laptop in the Middle East and went undetected as it spread across classified and unclassified networks, waiting quietly to send sensitive information to foreign servers. The breach led the Department of Defense to issue a total ban on USB drives in late 2008, which has since been changed. [WaPo]